Editors and contributors, Otávio Bueno, Ruey-Lin Chen, and Melinda Bonnie Fagan, do a remarkable job of not only articulating why the titular question “What things count as individuals, and how do we individuate them?” is of critical importance to contemporary scientific practice (and hence to contemporary philosophy of science), but also why one is unlikely to find a singular and definitive answer to the question. The book—starting with its comprehensive introduction—provides a crash-course on the various subproblems and subquestions that are associated with individuation in scientific theory and practice. 

Part 1—which concerns metaphysical and processual aspects of individuation—serves to emphasize (and often criticize) the limitations of monistic, substance ontological approaches for providing an account of individuation, especially in the biological sciences. The alternative to substance ontology is process ontology, and the strongest defense of it is found straightaway in Dupré (chapter 2), who leverages a process-based approach to defend pluralism about kinds, and therefore, about the way organisms are defined and classified. The crux of Dupré’s argument for a process-ontological approach to individuation rests in the “near universality” (27) of symbiosis (and other forms of codependency found among living creatures) and the subsequent permeability of the concept of a boundary. Dupré’s suggestion that the word “organism” has more than one intension (an organism can be denoted on the basis of genetic specifity [organism1], or on the basis of its capacity for ecological activity [organism2]) indicates that scientists’ theoretical purposes often determine what counts as the boundaries of an organism. Only a process-ontological approach to individuation can possibly account for the complex evolutionary trajectories that arise in a world where life is “massively collaborative” (28). The upside to Dupré’s pluralism is that it lends itself to novel ways of individuating biological entities—e.g., a focus on metabolic (or immunological) processes which serve to stabilize biological activity would afford new, more accurate classifications that are sensitive both to lineages of biological systems and to their particular environmental development. 

The downside to such pluralism is that it leaves unanswered difficult questions, such as how to individuate biological processes which make up organisms, and further, how to understand the part-whole relation that determines the structure and function of biological individuals. To this end, Pemberton (chapter 3) and Kaiser (chapter 4) do a great service in laying the groundwork for future research on these respective questions. The bulk of Pemberton’s essay consists in enumerating criteria for understanding what processes are, both within and beyond biology (his list identifies eleven unique points). The importance of conjuring up this list is that it illustrates the prodigious challenge that identifying principles for individuating processes involves. Perhaps not surprisingly, many of the items on Pemberton’s list that are identified as processes by science are identified as individual things by analytic metaphysics. This overlap presents an opportunity to test whether an “exemplar” (56) metaphysical view of individuals could resolve the titular question of individuation. Pemberton here draws on Lowe’s (2016) metaphysics of individuality to show that, indeed, there is a tension between how monistic and processual accounts identify individuals (especially individuals composed of parts that are themselves individuals) (56-7). Pemberton concludes that a processual view compels one to recognize both processes (and their parts) as being valid unities, whereas an exemplar metaphysical view lacks the tools to do so (though, it is not clear whether this validity is intended as an epistemic or ontological claim). In a similar fashion, Kaiser questions how we ought to understand the part-whole relation, asking “under what conditions is something a part of a biological whole?” However, unlike Dupré (and, to an extent, Pemberton), Kaiser’s answer to this question ventures a monistic account of the conditions that define parthood relationships; hence it applies to all cases, in all contexts, in all sciences. The two conditions Kaiser defends are substantial spatial inclusion (“x must be spatially located inside of or in the region that the natural boundary occupies if y has a natural boundary”) and compositional relevance (p is relevant to at least one of b1. . . bn; that is, p makes a necessary contribution to a condition that is minimally sufficient to one or more of b1. . . bn”) (81). Defenders of process-ontology may take solace in the fact that Kaiser’s account identifies the limitations of monism for defining biological part-whole relations.

Part 2—which concerns experimental practices of individuation—can be distinguished according to two themes: Where chapters 5, 6, and 7 provide theoretical and meta-theoretical perspectives on the topic of the individuation in the context of scientific practice, chapters 8, 9, and  10 provide detailed analyses of successful experimental practices and consider the practical importance of such successes. 

Waters (chapter 5) is very clearly cynical about theory-driven approaches to answering questions about individuation and boldly defends a form of pragmatism about such questions. His first foil is the concept of a gene: mirroring Dupré’s analysis of the organism concept, he explains that the individuation practices of geneticists entail a two-fold gene concept—one concept pertains to primary RNA molecules, whereas the other pertains to polypeptides (94-5). This “piecemeal” approach to individuation indicates that different concepts of individuality serve different aims. His second foil is the concept of the evolutionary individual. In canvassing accounts by Beatty (1982), Godfrey-Smith (2009), Clarke (2013), and McConwell (2017), he exposes a tension underlying the distinction between Darwinian individuals and holobionts. Rather than settling debates about which is a better candidate for an evolutionary individual, Waters emphasizes the descriptive virtues of these concepts, respectively, for different explanatory purposes (and purposes beyond explanation). This leads to his grand meta-philosophical conclusion, that one should ask not “what is an individual” but rather “what ways of conceiving biological individuality could be useful?” (111)

Fagan (chapter 6) and Griesemer (chapter 7) provide complementary responses to the Waters’ extreme pragmatism. Fagan’s contribution similarly emphasizes the significance of individuation practices but does so by taking a deep dive on case study of stem cells (rather than residing at the meta-theoretical level of analysis). For Fagan, stem cells express features—and processes—that are paradigmatic of organismal organization; for this reason, she argues that stem cells are to be considered a “model” organism for studying development (115). What makes stem cells potential models is that they (i) are not lone individuals but starting points for cell lineages, and (ii) they demonstrate self-renewal and differentiation spanning multiple generations. Drawing on McShea (2001), Fagan makes the case cultured pluripotent stem cells—those controlled and manipulated in the lab—are ontologically significant for debates about biological individuality given that they are “generative processes” which include organismal organization in their later stages (133). This both supports, and is supported by, process ontological approaches discussed in chapters 2 and 3. By contrast, Griesemer returns to the meta-theoretical domain and considers how the process-relativeness of individuals indicates different underlying conceptions of individuation. Like Waters, he believes that individuality concepts have a dual character and he commits himself to understanding the duality of this character from the perspective of evolutionary biology; however, unlike Waters, he sees the individuation question as unavoidable, arguing that the individuation question presupposes a prior one—namely, what are the units of selection in evolutionary biology? In focusing on this prior question, Griesemer distinguishes between empirical processes and tracking processes which differently construe what count as evolutionary individuals. His novel contribution is thus a meta-theoretical framework which identifies what kind of entities could potentially be units of selection based on the tracking processes biologists rely on to distinguish reproducers (these tracking processes are distinguished from empirical processes that are said to determine the evolution of reproducers) (152-7).

Love (chapter 8) ushers in the second half of Part 2 by rehearsing arguments by Clarke (2010, 2013) and Godfrey-Smith (2009) which make vivid the fact that the individual concept is in hopelessly confused and in dire need of cleanup. According to Love, Clarke and Godfrey-Smith both address this venturing (separate) accounts that posit that the mechanisms of individuation will form the basis of any fundamental theory of biological individuality. Love, following Kovaka (2015), sees such attempts as wrongly presupposing an asymmetrical relationship between theory and practice in biology, one which sees practice constrained by fundamental theory. Like both Fagan and Griesemer, Love demonstrates how individuation and tracking practices are illustrative of a underlying structure of scientific problems (he elaborates five), which gives rise to standardized practices in the research and comparison of results in laboratory settings. Because individuation practices are often than the starting points of experimental research, experimental practices should symmetrically inform and constrain theory. His thesis is applied to a case study in developmental biology on the problem of tracking growth (171-83). 

While still within the parameters of Part 2, Chen (chapter 9) and Guay & Sartenaer (chapter 10) usher forth a different perspective by considering (and contrasting) experimental practices in physics. Whereas previous chapters focused on the pragmatic/epistemic benefits of individuation practices to defend particular theoretical (or meta-theoretical) cases for pluralism, Chen aims to develop a general, positive account of experimental individuation that applies to all scientific practices. He argues that individuation consists in two modes of expression (or manifestation if you like)—one mode is experimental creation (an ontological mode), the other mode is experimental presentation (an epistemic mode). These modes of experimental individuation are thus explored via three cases: two cases from physics, i.e. the creation of Bose-Einstein Condensates and Fermionic Condensates, and one from biology, i.e. the presentation of genes. In addition to meeting the conditions of separability and manipulability, all three cases demonstrate that the task of experimentally individuating entities depends on the maintenance of their structural unity (207-10). Interestingly, Guay and Sartenaer take a different approach to analyzing individuation practices in physics. Their focus is the phenomenon of emergence and their concern is how to interpret emergent quantum particles, specifically anyons, which are produced during the fractional quantum Hall effect (FQHE). In defending emergentism as a scientifically and hence philosophically coherent position (cf. Laughlin 2005), Guay & Sartenaer consider two interpretations of FQHE and the production of anyons—these are referred to as mutualism and transformationalism. The chief difference between interpretations is that where mutualism requires “heavy metaphysical machinery” to justify the legitimacy of anyons’ emergent ontological status, transformationalism is light on the metaphysics—though, to appreciate this difference, one must attend to the physics of Humphrey’s account of transformationalism (225-9). Despite having potentially strong ontological and epistemic implications for the practice of individuation, Guay & Sartenaer have surprisingly little to say about the importance of emergentism for debates about individuation in the natural sciences. 

Part 3—which concerns individuation in relation to scientific realism, anti-realism, and environmentalism—continues with an initial focus on individuation practices in physics. Bueno (chapter 11) begins by presenting us the following conditional proposition: “if quantum objects are [by definition] non-individuals, how is it possible, even in principle, to identify and track them?” (239). His response points us toward a corresponding dilemma: in face of evidence which indicates that individuation is possible, one is either forced to revise (fundamental) theories which state that such objects can’t be tracked and individuated, or one must reinterpret empirical evidence to the contrary. With this dilemma in mind, Bueno explores three instances of supposedly successful individuation practices in physics: (1) trapping a positron and studying it’s behavior for an extended period time; (2) trapping an ion and performing similar studies on it; (3) manipulating and positioning single atoms with a scanning tunneling microscope (241-50). Bueno explains that how one interprets these achievements is critical to reconciling debates between realists and anti-realists about quantum objects—in particular, the successful trapping of a positron could vindicate realist arguments against empiricist anti-realists who hold that the scientific relevance of such objects does not depend on our ability to individuate and track them (i.e. observe them). Bueno concludes that, nevertheless, the problem of tracking is left open at the quantum scale (1), as opposed to nanoscales (2) and (3), and as such, the realist is not vindicated by such successes.

Hricko (chapter 12) and Millstein (chapter 13) bring the book to a close with two quite diverse chapters. Where Hricko pursues the realism/anti-realism debate introduced by Bueno in the previous chapter, Millstein diverges entirely, providing the sole contribution to the topic of environmentalism. Relative to the realism/anti-realism debate in philosophy of science, Hricko’s analysis is quite refreshing: his goal is to present and defend a subtler variation of realism, known as “retail realism” (Magnus & Callender 2004). Retail realism’s virtue is that it does not commit one to claims about the (ir)relevance of scientific objects across all debates, contexts, or scientific domains. One can be a realist with regard to some scientific entities, but an anti-realist with regard to others. The significance of this is as follows: for Hricko, being a realist about a particular object says (or should say) something about how one individuates that object. Hence, being a realist about a particular kind of entity can take different forms depending on how one individuates that kind of entity. Hricko thus justifies the position of retail realism by distinguishing between inclusive and exclusive individuation: because retail realism is more selective, it is consistent with exclusive individuation, which is also more selective about which entities are picked out by diverse theories (269-75). Finally, Millstein focuses on the question whether a “land community” can be construed as an individual. This question and her essay are based on pioneering work of Leopold (1949) and subsequent studies by Callicott (1987). In many ways, the question of individuating a complex biomass harken to discussions by Dupré (chapter 2) and Waters (chapter 5) who consider the challenges of demarcating systems composed of symbiotic partnerships. The challenge for Millstein in that the concept of a land community include far more than merely living entities in a shared metabolic or immunological system; it involves abiotic features as well (soils, waters, etc.). Millstein thus argues that while being an individual doesn’t oblige moral considerations, being an individual does make something a candidate for such considerations. After canvassing the semantic and associated methodological differences between community ecology and ecosystem ecology (286-91), Millstein determines that the land community concept as conceived by Leopold is consistent with contemporary ecology, and thereby, is at least a candidate for moral consideration and a possessor of intrinsic value.

In sum, this book effectively presents what could be construed as an argument against the appropriateness of analytic metaphysics to tackle issues concerning individuation and individuality. That’s not to say that scientists themselves don’t engage in metaphysical speculation from time to time (they do so more often than they realize); it’s to say that analytic metaphysicians are overly optimistic if they think questions about individuation and individuality can be (re)solved from the armchair. This book is a testament not just to the philosophical complexity of such questions, but also to the relevance of such questions for doing good science, and hence, for doing good philosophy of science.

Ⓒ 2020 James D. Grayot

James D. Grayot, Faculty of philosophy, University of Groningen